LCD玻璃基板之振動輔助劃線切割技術及原理

Abstract

本研究之目的在發展LCD玻璃基板之振動輔助劃線切割技術，方法是在控制劃線負載的機構上加裝一個壓電致動器，產生高頻振動，使劃線負載產生週期性的變化。本技術應用於標準型刀輪上，能大幅增加產生的中央裂紋深度達兩倍，並和有齒型刀輪一樣具有使玻璃自動裂開的能力，可以省略裂片程序。本技術可使玻璃切割後的彎曲強度保持標準型刀輪的水準，而避免有齒型刀輪造成玻璃強度不佳的缺點，若以此技術取代有齒刀輪，則可以節省刀輪及劃線設備成本。 本研究亦提出振動輔助劃線的原理，是屬於負載變動的效應。與一般劃線程序不同的是，變動的負載增加玻璃的彈性變形，而非塑性變形。由彈性變形增加中央裂紋深度避免了過去增加負載與塑性變形所造成的側向裂紋、徑向裂紋等缺陷。最後透過實驗證明振動輔助所增加的中央裂紋深度中具有非常顯著的彈性成分。

A technique of vibration assisted scribing of LCD glass substrate is developed in this thesis. An additional piezoelectric actuator is implemented on the servo controlled loading mechanism of the scribing machine, and a periodically varying load superposed on the constant load is provided to the standard scribing wheel. It is found that under a proper vibration frequency condition the median crack depth is significantly increased to about twice of that without vibration assisted scribing. As a result, automatic separation of the glass without the need of breaking process similar to the case with the use of toothed wheel (penett) can take place. On the other hand, while the bending strength of the glass panel after scribing by toothed wheel is merely about half of that resulting from scribing by standard wheel, it remains almost unchanged by the developed technique. Hence the cost of wheels and scribing machine can be reduced since toothed wheels can be replaced and the proposed technique can be applied by any commercially available machine. A fundamental theory of vibration assisted scribing process is also manifested. It is proposed that the rapidly varying periodical scribing load does not lead to as much an increase of the plastic deformation as that due to the servo controlled constant scribing load. Instead it mainly results in an increase of elastic deformation. The increase of median crack depth through elastic deformation can avoid the lateral and radial cracks induced by large plastic deformation which are usually observed under an increasing constant load condition. The noticeable elastic component of the increased median crack depth was confirmed by experiments, and the proposed theory is verified.